Fungal cultures on cyanoacrylate skin surface strippings as a dose-finding method for topical antifungals. A placebo-controlled study with 0.25% and 0.50% itraconazole cream.

The antimycotic activities of 0.25% and 0.50% itraconazole cream were compared in the stratum corneum after once-daily applications for 1 week. Two groups of 12 healthy volunteers applied either itraconazole or placebo on the inner side of each forearm, in a double-blind design. Cyanoacrylate skin surface strippings (CSSS) were taken on days 8, 11 and 21. Conidia or yeasts of selected fungi (Trichophyton rubrum, Trichophyton metagrophytes, Microsporum canis and Candida albicans) were deposited on CSSS. Fungal growth on CSSS was assessed in time by computerized image analysis to derive the inhibitory effect of the previously applied antifungal preparations. Comparable antimycotic activity was found against dermatophytes for both concentrations. Itraconazole 0.50% appeared to be more active than 0.25% against C. albicans. The 0.50% concentration yielded prominent fungitoxic effect after 1 week of treatment, and showed a lingering effect in the stratum corneum for at least 3 days. This method could be useful in a pre-clinical setting and serve as a predictive tool for further clinical dose-finding studies with topical antimycotics.